Brush spring retractor



Oct. 13, 1953 H. A. KRAUSE BRUSH SPRING RETRACTOR Filed Jan. 12, 1949 Fatented Oct. 13, 1953 BRUSH SPRING RETRACTOR Herbert A. Krause, Brookfield, Ill., assignor to General Motors Corporation, Detroit, Mich, a

corporation of Delaware Application January 12, 1949, Serial No. 70,506

4 Claims.

This invention generally relates to hand tools and more particularly to a tool for retracting brush fingers of dynamoelectric machines.

The principal object of the invention is to provide a hand tool which may be readily engaged with brush fingers in the confined space they occupy within the frame of a dynamoelectric machine adjacent a commutator or the slip rings of such machines.

The various features of my brush finger retracting tool will become apparent by reference to the following detailed description and drawings of this tool.

Figure 1 of the drawings is an enlarged perspective view of a portion of the tool, shown in engagement with a brush finger of a brush holder of a dynamoelectric machine, with parts broken away.

Figure 2 is a vertical elevation of the tool.

Figure 3 is a sectional view taken on line 3-3 of Figure 2 with parts shown broken away and in section.

Figure 4 is an enlarged perspective view of a part of the tool engageable with the finger to be retracted.

Figure 5 is a plan view of the tool with parts broken away and in section.

Figure 6 is a vertical elevation of the tool with the parts shown broken away and in section and in different operative relation.

As best illustrated in Figure 2, the tool comprises an L shaped tool head, generally indicated at I, and a lever, generally indicated at 3 and pivotally connected to the head. A handle 5 is secured to the outer end of the lever 3 and is shown extending along one side of the head and provided with a circular transverse inner end pivot portion I extending through a transverse hole 9 in the vertical arm 3 of the head adjacent the upper end for angular and axial movement therein. A lug II is secured to the outer end of the pivot portion I and extends along the other side of the head toward the outer handle end of the lever 3 as best illustrated in Figures 1, 3 and 5. The head is also provided with a hole I3 normal to and intersecting the transverse hole 9 and a helical compression spring I5 is positioned in the hole I3 between the bottom thereof and the pivot portion I of the lever 3, as best shown in Figure 3, to exert suificient frictional force therebetween to prevent relative angular and axial movement of these parts. An abutment plate I! is secured to the upper end of the vertical head arm 8 adjacent the transverse hole I3 and this plate extends beyond the sides and one end thereof and forms side and end abutments engageable by the lever 3 or the lug I I thereon. It will be evident that, if the lever pivot portion I ismanually moved axially sidewise in the direction of the arrows shown in Figures 1, 3 and 5 to the full line position with respect to the head arm 8 against the frictional force exerted by the spring I5, the lug I I on the outer end of the lever pivot portion I is positlsned below the projecting end and one side portion of the head abutment plate I1 and subsequent clockwise movement of the lever 3 and handle 5 thereon with reference to the head I, as shown by the arrows in Figures 1 and 2, causes the lug II to contact and move the head in the same direction. Conversely if the lever pivot portion 1 is moved axially in the opposite direction with respect to the head to the dotted line position, Figure 5, the lug II is positioned beyond the projecting end and other side portion of the head abutment plate I1 and subsequent clockwise movement of the lever and handle thereon causes the lever to contact the abutment plate and move the head in the same direction.

The other horizontal leg IQ of the head I extends longitudinally inwardly toward the lever handle 5 below the transverse hole 9 in the vertical leg 8 through which the lever pivot portion 1 extends. A U shaped bracket 29 having upstanding legs 2 I23 embracing and secured at the upper ends to each side of the outer end portion of the horizontal head arm I9 to position the bottom portion 25 of the bracket vertically downwardly from the arm, to form an open ended socket portion 21 between the arm I9 of the head and the legs 2I--23 and bottom 25 of the U shaped bracket 20 secured thereto. The bottom 25 of the bracket is provided with an upturned abutment or lip 29 adjacent the outer end of the socket 21 as best seen in Figure 6.

Depending upon the limited space available adjacent the brush finger of the dynamoelectric machine to be retracted by this tool the lever 3 is positioned transversely and angularly relative to the tool head I in which position it is normally held frictionally by the helical spring I5 for engagement of the lever I or lug II thereon with the abutment plate I? so that the socket portion 21 in the outer end of the horizontal arm 19 of the tool head I may be readily engaged with the outer end surface of a brush finger 3I by manipulation of the lever handle 5, as best shown in Figure 1, with the horizontal arm I9 of the tool head I above and parallel to the upper end surface of the finger. The brush finger 3I, shown in Figure 1, is a radial end portion of a spiral brush spring 32, the other end of which is secured by a pin 33 to a brush holder 35 provided with a brush slot 3'! adjacent the outer end of the finger. The finger 3| has a pad 39 secured to the lower face adjacent the outer end and normally urged by the spring portion 32 toward the outer end of the brush slot to urge the finger pad 39 into contact with the outer end of a brush 4|! in the slot 31 in order to retain the inner end of the brush in contact with the outer surface of a dynamoelectric machine armature or slip ring, not shown, in conventional manner. The outer end of the finger 3| is shown in Figures 1 and 2 extending into thesocket 21 between the horizontal head arm l9 and the U shaped bracket 20' with the Outer end of the finger pad 39 in engagement with the inner end surface of the bracket lip 29, to limit further movement of the head arm on to the finger.

With the finger 3| located in the socket .21 of the tool head I in the above described manner and the head abutment plate I! engageable by the lug II on the lever 3, as shown in Figures'l and 3, or with the'lever engaged with the head abutment, as shown in dotted linesin Figures 1 and 5,if sufficient space is available adjacent the'tool handle 5 it may be moved outwardly clockwise with reference to the finger 3| as shown by the arrows-in Figures 1 and 2 to transmit clockwise retracting movement to the finger 3| touncover the outer end of the brush holder slot 31 in order that the other hand of the tool operator may readily and'safely insert and remove the brush at from the brush holder-slot 31.

If there is not sufficient space available to move the handle 5 outwardly clockwise an amount necessary to fully retract the finger the handle 5 and lever 3 may be moved counterclockwise or inwardly-with reference to the head I and finger 34' to a position below and at an angle to the brush finger 3| so that an angularly upwardendwise thrust-may be exerted on-thehandle 5 and lever to causeretraction of the finger 3|. The relative position of thelever 3 relative tothehead and finger 3| when so retracted isshown in dotted lines'i-n- Figure-2 and the direction of thrust on the lever being indicated by the dotted arrow. If there is not sufficient clearance to rotate the handle 5 relative tothehead t from the full line position shown in Figure 2- an endwise thrust on the lever-3 in the direction of the arrow will' likewise causeclockwise-retracti'ng'movement of the tool head and brushfinger '3'| asthe lever 3 is pivoted to the vertical arm 8 of the head in vertically offset relation with respect to the point of engagement of brushfinger'3l by the horizontal arm |'9 of the tool head.

In order to engage certain otherwise inaccessible brush fingers 31 the "complete retracting tool may be inverted and the head-1 rotated approximately a half revolution withrespect to the lever 3 tothe position 'shown'in full lines in Figure 6 to also enterthe outer end of the brush finger into the socket portion-"21' of the tool head so that the outer end of the finger pad 39' is contacted by the outer end surface of the lip or abutment 29 toretract the finger by either an'angular movement of orby the appli cation of an endwise force" on the lever handle- 5 in the previously described manner.

This brush finger retracting tool' enables safe removal and replacement of brushes in brush holders located in various and otherwiseinaces-- sible positions within dynamoelectric machines.

I claim: 1. In a retracting tool for an angularly retractible brush finger, a tool head having means' in one end engageable'with oneend of the-brush fingeryan elongated lever having a transverse 4 for lateral and angular movement with respect to an axis located in vertical offset relation to said'finger engaging means-of saidhead, said head having abutments thereon spaced laterally apart, said lever also having surfaces spaced laterally apart, each lever surface contacting one .ofsaid-head abutments upon lateral and angular movement of said lever thereby causing angular movement of said head and angular retracting movement of'the brush finger, said lever being also movable endwise of the lever pivot and the offset-brushfinger engaging means of said head when engaged with a brush finger to cause relative angular movement of said head and corresponding angular retracting movement of the finger.

2. In a retracting tool for an angularly retractible brush finger, a tool head having angularly ofiset legs, one leg having brush finger engaging means, a lever mounted at one end for lateral and. angular movement in the other leg of the head, frictional means engaging said'hea'd and lever to restrain relative lateral and'angular motion between said head and said lever, said head having laterally spaced abutments, and said lever having a pair of abutments spaced laterally apart a greater distance each engage able with a head abutment upon lateral and angular movement of said lever to transmitangular movement to said head to angularly retract the brush finger engaged thereby, the offset mounting of said lever and said finger engaging means on said head also causing relative angular movement of said head relative to the lever L to retract the brush finger when the lever is moved endwise toward the end of the brush finger engaged by said head.

3. A tool for retracting brush fingers (an-dynamoelectric machines comprising a lever having a lateral arm rigidly attached thereto -and an L-shaped head having a base portion and a leg portion and fastened to saidarmv for pivotal and extended axial movement with respect thereto, the base portion of the L-shaped head containing said lateral arm and its a'xi's, said axis being perpendicular to the leg portion of said L-shaped head, and the unattached end of-the leg of said L-shaped head being provided with brush finger engaging. means, whereby whenaxial movement is. givento said lever, said-head and a brush finger which said means is adapted to engage are angularly displaced.

4. A tool for retracting brush fingers on dynamoelectric machines comprisinga lever having a lateral arm rigidly attached thereto, a

head provided with an abutment andfastened to said arm for pivotal and extended axial movement with respect thereto,.means rigidly attached to said arm adapted to engage said abutment and prevent pivotal movement of said head with respect to said arm in one rotative direction only, and brush finger engaging means on said head, whereby leverage and axial movement may be applied to said lever to angularly displace said head and brush finger.

HERBERT A. KRAUSE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,247,729 Scribner Nov. 27, 1917 1,630,296 Heesch May 31, 1927 1,844,433 Markowitz Feb. 9, 1932 1,888,269 Herst Nov. 22, 1932' 

